Cellulosic fabrics and methods for making the same



United States Patent 3,175,875 CELLULOSE FABRICS AND METHODS FOR MAKlNGTHE SAME Dmitry M. Gagarlne, Spartanburg, S.C., assignor to DeeringMiliiken Research Corporation, Spartanburg, S.C., a corporation ofDelaware No Drawing. Filed Apr. 25, 1960, Ser. No. 24,265 25 Claims.(Cl. 8-120) This invention relates to methods for treating cellulosictextile materials to improve certain characteristics thereof and to thefabrics thus obtained. This application is a continuationin-part of mycopending applications Serial Number 789,798, filed January 29, 1959,and Serial Number 677,204, filed August 9, 1957, now abandoned, andSerial Number 575,516, filed April 3, 1956, now US. Patent 2,985,501.

According to this invention, a cellulosic textile material containingfree hydroxy groups is subjected to the combination of steps of firstcross linking a sufiicient portion of the free hydroxy groups while thecellulosic fibers are in an essentially dry, unswollen condition and thematerial is in an essentially wrinkle free configuration to impart dripdry fiat drying properties to the material and then cross linking asufficient portion of the free hydroxy groups while the cellulosicfibers are in an essentially wet, swollen condition and the material isin an essentially wrinkle free configuration to impart spin dry flatdrying properties to the material.

It is now well known that cellulosic fabrics can be treated with atextile resin to impart certain minimum care characteristics, i.e., flatdrying properties, thereto and many such fabrics have been marketed. Itis a characteristic of such fabrics, however, that they must normally bedrip dried, i.e., hung to dry while dripping wet in order for them tohave a semblance of a pressed appearance when dry and thischaracteristic has somewhat limited their commercial success. In otherwords, resin treated fabrics, while possessing improved dry creaserecovery, do

not possess good spin drying properties. Another disadvantage of theprior art resin treated minimum care fabrics is that they have either aharsh hand or insufficient wrinkle resistance as it has been found thatin order to impart a relatively high degree of wrinkle resistance to acellulosic fabric, it is normally necessary to employ such a largeamount of the textile resin that that the hand of the treated fabric isrough. Further, even when these large amounts of the textile resin areapplied, the fabric often does not have as high a degree of wrinkleresistance as is desired. Moreover, large amounts of textile resinsreacted with cotton fabrics embrittle the fibers, i.e., lower their tearand tensile strength and/or flex abrasion resistance, and render themless serviceable in normal wear.

It is now known to modify cellulosic fibers by reacting them with wetcross linking agents, i.e., cross linking agents which will react withthe fibers while the fibers are in a wet, swollen condition, includingthose which can be employed in the process of this invention. Forexample, divinyl sulfone, epichlorohydrin and glycerol dichlorohydrinhave been found to be as suitable wet cross linking agents to producefabrics having flat drying properties. See e.g., US. 2,985,501.

However, all of the known wet cross linking agents while giving variousdegrees of spin dry fiat drying propice erties to cellulosic textilefabrics, i.e., wet crease recovery, do not give the dry crease recoveryor wrinkle resistance that is obtainable with the resin treated fabrics.They therefore cannot be tumble dried with satisfactory results.

Thus, heretofore, it has not been possible to produce a commercialproduct having good flat drying properties under all conditions, e.g.,spin dry followed by line or tumble drying, as well as good wrinkleresistance.

it has now been found that a resin treated, wet cross linked cellulosictextile material obtained according to the process of this invention hasall of the aforesaid desirable can be obtained that is greater thanwould be obtained employing the same amount of the textile resin aloneand also that lesser amounts of textile resin are required to achieve adegree of dry crease recovery or drip dry flat drying properties thesame as or better than that obtained when employing a resin treatmentalone. The improved hand and appearance and the improved launderingcharacteristics of the finished fabric are of considerable importance.

As will be discussed more fully hereinafter, outstandingly desirableresults are obtained when the textile material is resin treated firstand then treated with the wet cross linking agent. This result issurprising in view of the fact that the wet cross linking agentsemployed in this invention are often and preferably catalyzed. withrelatively strong aqueous alkali and it is well known. that many resintreated fabrics will lose their enhanced dry crease recovery in thepresence of strong alkali. It would therefore be expected that thealkali employed in such a subsequent Wet cross linking step would harmthe resin treated textile material and reduce the dry crease recoverythat would otherwise be obtained. However, quite the opposite effect isobtained, i.e., not only is dry crease recovery not reduced but it isoften materially increased. Further, the durability of the resintreatment is materially enhanced when used in conjunction with a wetcross linking step, i.e., some resins lose their good dry creaserecovery after repeated washings and the process of this inventionprevents this rapid loss.

It is an object of this invention to provide a method for producingresin treated cellulosic fabrics having improved dry crease recovery.

It is another object to provide a method for producing resin treatedcellulosic fabrics having good dry crease recovery while employinglesser amounts of textile resin than heretofore required.

Another object is to provide a method for preventing resin treatedcellulosic fabrics from losing their dry crease recovery after repeatedwashings.

Another object is to provide a method for producing resin treatedcellulosic fabrics having improved hand and/ or spin dry properties.

Another object is to provide a method for producing wet cross linkedcellulosic fabrics having improved dry crease recovery.

Another object is to provide a method for producing wet cross linkedcellulosic fabrics having improved tumble dry properties.

Another object is to provide a method for producing wet cross linkedcellulosic fabrics having both improved spin drying properties and drycrease recovery.

Still another object is to provide cellulosic fabrics having bothincreased spin drying properties and dry crease recovery, as Well asother desirable properties, as compared with fabrics resin treated orwet cross linked alone.

Other objects will be apparent to those skilled in the art to which thisinvention pertains.

The objects of this invention can be achieved by cross linking the freehydroxy groups of cellulosic fibers of textile materials according toprocedures described hereinafter.

The term flat drying means a fabric which when washed, tends to dry inan essentially wrinkle free condition. The degree of fiat dryingproperties of a fabric can be determined by A.A.T.C.C. Test DesignationT-88- 1958. Commercial Wash and wear fabrics usually have a fiat dryrating by this test, after drip drying, of at least 3.5 and the termflat drying when used herein means a fabric having a rating of at least3.5 by this test. It is also recognized in the art that fabrics having arating of at least 4.0 by this test are preferred and the process ofthis invention, in its preferred ramifications, is directed to theproduction of fabrics having at least a 4.0 rating.

The term drip dry fiat drying properties when used herein means theability of a fabric to dry in an essentially flat, i.e., reasonablywrinkle free condition, when hung dripping wet to dry.

The term spin dry flat drying properties when used herein means theability of a fabric to dry in an essentially flat, i.e., reasonablywrinkle free condition, when damp dried in the spin cycle of anautomatic washer and then hung to dry on a line.

The term resin treatment is one commonly used in the textile art andrefers generally to a process whereby a fabric is contacted with areagent reactive to cellulose, and usually an acid acting catalyst,dried if moisture is present, e.g., from room temperature to 149 C., andthen cured, i.e., reacted with the fabric in its dry state, at a highertemperature, e.g., 140 C. to as high as 200 C. to produce a fabrichaving improved dry crease recovery. At this temperature, many of thesereagents, even by themselves, will resinify in the presence of theappropriate catalyst, thus probably contributing to the use of the termresin treatment.

In other words, in the textile art resin treatment means a process inwhich a fabric in its dry state, i.e., the fibers are essentially dryand unswollen, is heated or cured at an elevated temperature whileimpregnated with the selected reagent and a catalyst for the reaction.

Along with the use of the term resin treatment, the textile art has alsoadopted the practice of using the term resins to define the reagentsemployed in this resin treatment and distinguish them from sizes whichmerely coat the fibers, although the term is a misnomer in that incontradistinction to the generally accepted meaning of the term resin,these textile reagents have relatively low molecular weights, are almostalways water soluble and are often liquids. Therefore, in conformitywith the generally accepted usage in the textile art, the term resin ortextile resin, when used herein, defines those classes of reagentscommonly employed in the textile art for the resin treatment of fabricsas described above.

The textile resins which can be employed in the process of thisinvention include the low molecular weight, e.g., usually less than1,000, water soluble acid or acid salt catalyzed materials which arethermosetting in the presence of cellulosic materials as definedhereinafter. There are many textile resins commercially available. The

largest class of known textile resins are the aminoplast resins formedby reacting compounds such as urea and melamine with formaldehyde.Specific examples of textile resins within this class include ureaformaldehyde textile resins such as the resin commercially available romRohm & Haas under the trade name of Rhonite 610"; methyl ethers of ureaformaldehydes such as the resin sold by Rohm & Haas under the trade nameof R2 Resin; acrolein urea formaldehyde resins; cyclic ethylene ureaformaldehyde resins such as the resin sold by E. I. du Pont under thetrade name of Zeset and the textile resin sold by Rohm & Haas under thename of R-1 Resin; trimethylol acetylene diurea; tetramethylol acetylenediurea; melamine formaldehyde textile resins, such as the resins sold byMonsanto under the trade names of Resloom HP. and Resloom L.C.,including the methylated melamine formaldehyde textile resins such asthe resin sold by American Cyanami-d under the trade name of M3 Resin;or the textile resin sold by Monsanto under the trade name of M- Resin;copolymers such as a copolymer of melamine formaldehyde and ethyleneurea formaldehyde; and the textile resins known to the trade as urons,one of which has the formula:

In addition to textile resins of the above type, one can suitably employpolyepoxy resins which come within the general group set forth above.Examples of suitable resins of this class include the triglycidyl etherof glycerol, and the diglycidyl ether of glycerol, sold by ShellChemical Company under the name of Eponite 100. Still another class oftextile resins which can suitably be employed are the triazone resins.Still another resin which can be employed is the tris-(1-azirindinyl)phosphine oxide which is prepared by reacting three molesof ethyleneimine With one mole of P0013 and which is known to the tradeas APO Resin or lmine LP. Resin. One need not employ a single textileresin but can employ mixtures of the above type resins or copolymersthereof. Likewise, it is not necessary that the resins be entirely freefrom water-insoluble components since it has been found that dispersedparticles of water-insoluble materials in the resin solution are notdeleterious even though any portion of the resin that is water-insolubleprobably does not contribute to the beneficial results ob tainableaccording to this invention. Some of the commercially available resinsmentioned above contain small percentages of water-insoluble polymericmaterials and while an aqueous mixture of such resins can be filtered ifdesired, equally satisfactory results are generally obtainml byemploying the unfiltered material.

As stated above, some textile resins can be catalyzed by an acid actingcatalyst, i.e., acidic in character and others by an alkaline catalystalthough most of the textile resins employed today are catalyzed by acidacting catalysts.

Suitable acid acting catalysts for resins of the above types are wellknown in the tart. Urea formaldehyde and melamine formaldehyde resinsare best catalyzed by hydrochloric o r nitrate salts of hydroxyalkylamines such as monethanol amine hydrochloride or2-amino-2-methylpropanol nitrate. Cyclic ethylene urea formaldehyderesins, acetylene diurea formaldehyde and uron resins are preferablycatalyzed by zinc nitrate or by magnesium chloride. The epoxy resins arepreferably catalyzed by hydroxy groups. transformed in situ as a resultof the action of the basic acid fluoride salts, such as the catalystcompositions available from Shell Development Company under the tradenames of Curing Agent 48 and Curing Agent 20.

The amounts of catalyst desirable to be employed are well known in theart. Generally any amount of catalyst up to about 20% by weight of theresin mixture will give satisfactory results with the preferred rangebeing from about 0.5% to about 10% of the resin solids employed.

The term wet cross linking agent is used in this specification todistinguish compounds employed to cross link the cellulose under aqueousconditions from the textile resins described hereinbefore. They arecharacterized by the ability to react, or to be converted in situ tocompounds which will react, with the free hydroxy groups of thecellulosic fibers of the fabric being treated according to the processof this invention, while the fibers are in a Wet, swollen condition.Textile resins, on the other hand, do not properly react with thecellulosic fibers while they are in a wet, swollen condition, probablybecause the textile resin has a greater inclination to react with waterat the elevated temperature employed in resin treatment, than with thefree hydroxy groups of the cellulosic fiber.

There are numerous reagents known in the art which can be characterizedas wet cross linking agents. They are generally characterized by beingbifunctional, i.e., having at least two groups which will react, or areconverted in situ to groups which will react, with the free hydroxygroups of the cellulosic fibers.

A catalyst is ordinarily required to produce the desired wet crosslinking reaction. These can be either alkaline catalysts or acidiccatalysts, depending upon the character of the wet cross linking agent.The dihalohydrins, i.e., those having either a pair ofhalohydroxy-ethylene groups or an alpha halogen atom on each side of thehydroxy grou the diepoxides, the epoxyhalohydrins and the a-haloepoxidesare examples of the alkaline catalyzed wet cross linking agents.Examples of acid catalyzed wet cross linking agents are formaldehyde,glyoxal, et-hydroxy adipaldehyde, phenylglyoxal, a-keto-acetaldehyde anddiacetyl.

The preferred Wet cross linking agents and those which ordinarily givebest results are the alkaline catalyzed compounds. Preferred arnong thisgroup are those containing from 3 to 15 carbon atoms, inclusive, e.g.,those which produce cellulosic cross linkages of from 3 to 6 carbonatoms in length. The bridging chain formed by the cross linking agentcan contain, depending on the choice of wet cross linking agent,elements other than carbon and, in fact, in all instances the crosslinkage will contain oxygen as the cross linkage as a result ofetherification of hydroxy groups of the cellulose. In addition to oxygenand carbon, the linkage may also contain nitrogen, phosphorus, sulfur,silicon, or other polyvalent elements known to form stable organiclinkages.

Likewise, the cross linkage may contain substituent groups or sidechains. Examples of substituent groups which may be present include ketogroups, hydroxy groups, halogen atoms, and methyl groups, although thepresence of such substituent groups ordinarily is not preferred and thenumber and size of these substituent groups should be such that themolecular weight of the divalent radical connecting thecellulosereactive groups of the cross linking agent is not in excess ofabout 260. It should also be emphasized that the preferred alkalinecatalyzed wet cross linking agents, while spoken of as having two ormore reactive groups, need not possess groups, as it is initiallyemployed in the process of this invention, which are capable of reactingdirectly with The reactive groups can suitably be catalyst to giveconnective groups capable of reacting with cellulose, as in the case ofthe halohydrins.

Alkaline catalyzed, wet cross linking agents within the above generalclassification can be divided into three general classes. A first classcomprises the polyepoxy cross linking agents including diepoxybutane;the diglycidyl ether of ethylene glycol, propylene glycol, or diethyleneglycol; the triglycidyl ether of glycerol; and the diglycidyl ether ofbisphenol A; and compounds having an a-halohydrin group, e.g.,chlorohydrin or bromohydrin, in place of one or more of the epoxy groupsand compounds having a halogen atom, e.g., chlorine or bromine, on acarbon atom adjacent either an epoxy group or a halohydrin group.Examples of such latter compounds are epichlorohydrin,1,3-dichloropropanol-2, 1,3-dibromopropanol-Z, andbis-(1-chloro-Z-hydroxy-n-propoxy)ethane. A second class of preferredalkaline catalyzed wet cross linking agents include the sulfoneactivated divinyl compounds. Examples of this c ass of compounds aredivinyl sulfone, bis-(vinyl sulfonyl) methane, and 1,4-bis- (vinylsulfonyl)butane. A third class of alkaline catalyzed wet cross linkingagents are the carbonyl activated divinyl compounds, e.g., divinylketone, and octa-l,7-diens-3,6-dione. A fourth class are the carbonyland sulfonyl activated sulfuric acid and phosphoric acid esters andtheir alkali metal salts, e.g., disodium bissulfatoethyl sulfone.

The above-described first class of compounds are, generally speaking,the preferred class of alkaline catalyzed wet cross linking agents. Aconsiderable number of known compounds fall within this class. Thesecompounds can be represented by one of the formulae:

represents a divalent radical represented by one of the formulae whereinR and R in each instance, represent hydrogen or a monovalentnonfunctional radical, and X represents halogen, preferably chlorine orbromine.

R R R and R in the above formulae, in each instance, preferablyrepresent hydrogen, as such compounds are the most readily prepared, butthey can in one or more instances represent lower alkyl groups, e.g.,methyl or ethyl, hydroxyalkyl groups, e.g:., hydroxymethyl orhydroxyethyl, monocyclic aryl groups, e.g., phenyl or tolyl, cycloalkylgroups, e.g., cyclohexyl, haloalkyl groups, e.g., chloromethyl orchloroethyl, or R and R can together represent a divalent connectingradical, e.g., methylene, ethylene or other lower alkylene radicals. Rcan represent any divalent connecting radical group but in mostinstances will represent either an alkylene group, e.g., methylene,ethylene, or propylene, a hydroxyalkylene group, e.g., hydroxypropyleneor a group of the formula --RY--R-YR, wherein Y represents oxygen orsulfur, R and R represent lower alkylene groups, e.g., methylene orethylene, and R represents any divalent con necting radical, asillustrated by a lower alkylene group, a lower hydroxyalkylene group,e.g., Z-hydroxypropylene, a monocyclic aryl radical, e.g., phenyl ortolyl, a radical i of the formula -C H (O-C H wherein n is an integer offrom 1 to about 20, or a radical of the formula (R"-O-CH --CHCH O) R"-,wherein n linking compounds are:

represents an integer of from 1 to about 5 and R represents a divalenthydrocarbon radical as illustrated by Compounds of the latter typeresults when epichlorohydrin is reacted with less than an equal molarquantity of a dihydric alcohol or phenol. When a wet cross linkingcompound corresponding to one of the formulae in mixtures thereof.

The type and amount of catalyst to be employed de pends upon whether anacid or alkaline catalyzed wet cross linking agent is employed and uponthe reactivity of the selected wet cross linking agents. These catalystsand the amounts to be employed are known in the art.

Suitable alkaline catalysts for the alkaline catalyzed wet cross linkingagents include the alkali metal hydroxides, e.g., sodium hydroxide andpotassium hydroxide, the quaternary ammonium hydroxides, e.g.,trimethylphenylammonium hydroxide, tetrabenzylammonium hydroxide, andtetramethylammonium hydroxide, and alkali metal salts which, in thepresence of water, produce a strongly alkaline solution, e.g., thealkali metal sulfides. When the salts are employed, they should beemployed in an amount which will impart an alkalinity to the solution inthe same .range as that obtained when an alkali metal hydroxide or.quaternary ammonium hydroxide is employed. Generally speaking, a molarequivalent or more of the salt, based on the amount of an alkali metalhydroxide which would give satisfactory results, should be employed.

The acid catalyzed wet cross linking agents are ordinarily catalyzedwith strong mineral acids, including hydrochloric, sulfuric andphosphoric acids, although the stronger organic acids are also operable.The amounts of these acids to be employed generally correspond to theamounts employed when an alkali metal hydroxide is employed inconjunction with an alkaline catalyzed wet cross linking agent.

The term cellulosic textile material when used herein means any textilematerial comprising fibers having the free hydroxy groups characteristicof cellulose, e.g., cotton, unmodified cellulose and cellulose modifiedby etherification or esterification of a portion of the hydroxy groups.Textile materials within this definition include those comprisingnatural cellulose fibers, e.g., cotton, linen, jute, flax, regeneratedcellulose fibers, e.g., viscose rayon fabrics, and cellulosic fiberssome of the hydroxy groups of which have been replaced by ester or ethergroups, so long as some free hydroxy groups are present so as to obtainthe desired cross linkage. Normally, cellulosic fibers which contain asfew as 1.8 free hydroxy groups per anhydroglucose unit will result insufficient cross linkage for satisfactory results. Thus, cellulosictextile 'materials the fibers of which contain a limited number ofacetyl groups, such as cellulose acetate fabrics of a relatively lowacetyl content, or textile materials the fibers of which contain alimited number of methyl ether groups, such as partially methylatedcellulose, can be processed according to this invention. However,textile materials which do not comprise cellulosic fibers having freehydroxy groups are not normally suitable for use in the process of Ithis invention and are not within the term cellulosic textile materialas used herein.

Although this invention is directed primarily and preferably tocellulosic textile fabrics, both knitted and woven, the advantages ofthis invention can also be achieved by treating the cellulosic yarns orthreads employed to produce these fabrics. Ordinarily, this will becotton thread or yarn. The thus treated thread or yarn, when woven intofabric, will produce a fabric having better fiat drying properties thanidentical fabric woven from untreated yarn or thread.

Satisfactory results, according to this invention, can be achievedemploying cellulosic fabrics containing both cellulosic andnoncellulosic fibers, especially if the noncellulosic fibers have someminimum care characteristics of their own. For example, the minimum carecharacteristics of fabrics formed from a mixture of glycol-terephthalatefibers and cotton fibers can be improved by the process of thisinvention even if the percentage of cotton fibers is small, e.g., 10% to40%. Satisfactory results can also be obtained with fabrics formed froma mixture of nylon fibers and cellulosic fibers or a mixture ofcellulosic fibers and polyacrylic fibers, e.g., those sold under thetrademark Orlon. As would be expected, if the noncellulosic fibers havelittle or no minimum care characteristics, the improved characteristicsof the fabric treated according to the process of this invention will bemore readily apparent if the cellulosic, e.g., cotton, content of thefabric is substantial, e.g., about 40% or more by weight.

Because Woven fabrics consisting essentially of cotton, e.g., 100%cotton, ordinarily have the poorest fiat drying and dry crease recoveryamong the common cellulosic textile fabrics, the advantages of theprocess of this invention is most readily apparent with these fabricsand it is to these fabrics that this invention is preferably directed.

The resin fixation is performed While the cellulosic fibers are in anessentially dry, i.e., unswollen configuration. It appears that theresin fixation tends to fix or stabilize the fibers so that theresultant fabric tends to maintain itself in the configuration itpossessed during the resin treatment, thus giving it improved dry creaserecovery, i.e., wrinkle resistance. However, it is well recognized thatwhen the fabric is subsequently moistened, the fibers become mobile and,if wrinkled or creased while in this moist state, they will dry withsome of the creases or wrinkles retained. It is for this reason that itis recommended that the socalled wash and wear resin treated fabrics ofthe prior art be drip dried, i.e., dried while the fabric issubstantially wrinkle free. Thus, the housewife, in washing this fabricin an automatic washer, must remove the fabric without spin drying. Theinconvenience of this procedure has tended to limit the commercialacceptance of wash and Wear resin treated fabrics, although thesefabrics, when properly dried, do reduce ironing time.

The wet cross linking process of the prior art, while improvingdimensional stabiiity and shrinkage resistance, generally have notproduced a commercially acceptable spin dryable product, i.e., onehaving suitabl wet configuration memory. In my copending applicationSerial Number 575,716, there is described a technique for achieving thedesired spin drying properties, employing classes of reagents some ofwhich are known to the art. The products produced by this improvedprocess produce an excellent spin drying product, an important anddesired property. Thus, the housewife can spin dry and then line dry agarment made of the thus treated fabric, thereby eliminating thenecessity of interrupting the normal cycle of an automatic washer andhanging dripping wet garments to dry.

Such improved products do not, however, possess dry crease recovery tothe desired degree. Retailers, for example, desire a product which willhang substantially wrinkle-free when removed from shipping boxes orstorage drawers. It appears that wet cross linked fabrics, while tendingto retain a desired configuration while in a moist or wet condition, donot have this characteristic to an appreciable degree when thecellulosic fibers are in a dry, unswollen condition. Thus, tumble dryingtends to impair the appearance of a spin dried garment or fabric whichhas been wet cross linked.

The process of this invention produces a fabric having both good spindrying properties and good dry crease recovery. Not only is the combinedadvantages of resin treatment and of wet cross linking observed, butadditional surprising advantages are obtained that could not bepredicted from the results obtained from either of these treatmentsalone. Some of these advantages are described hereinbefore.

In carrying out the process of this invention, the cellulosic textilematerial is dry treated, cross linked, e.g., by a conventional resintreatment, and then wet treated, i.e., wet cross linked, while thematerial is in a wrinkle free configuration. This can be accomplishedaccording to techniques known in the art.

The resin treatment involves the well known steps of applying a textileresin and catalyst, if necessary, usually as an aqueous solutionthereof, ordinarily squeezing the material through rollers to achievethe desired solution take-up, drying and then curing the material at anelevated temperature to achieve the desired reaction of the textileresin with the cellulosic fibers, with the latter step being performedwhile the material is maintained in a wrinkle free configuration, i.e.,ordinarily an essentially flat condition. Plat, in this sense, includesrolling up smooth into a roll.

Conventional equipment is suitable for this operation. For example, thetextile resin can be applied with the usual padding equipment, thematerial then passed through squeeze rolls, and then dried, e.g., atroom temperature or while the material passes through a hot air ovenand, if fabric is being treated, preferably while in a tenter frame tomaintain the desired dimensions. The usual curing equipment can beemployed for the curing step, so long as the material is maintained in awrinkle free condition. If a hat fabric is desired, the usual stationaryor rotating tenter apparatus can be employed. However,

, if a novelty fabric is desired, e.g., an embossed or a pleated fabric,drying and curing of the fabric should be performed under conditionsapproximating this condition, but nevertheless free from extraneouswrinkles. The material can then, if desired or necessary, be scoured toremove any excess reactants or residual catalyst.

Further details of the general methods of textile resin treatment areset forth in publications such as, for example, Marshs An introductionto Textile Finishing, Wiley Publishers (1951), and Wards Chemistry andChemical Technology of Cotton, lnterscience Publishers (1955).

The amount of textile resin which is applied to the cellulosic textilematerial according to this invention can be varied within wide limits,e.g., between about 2% and about resin solids, calculated on the weightof the dry fabric. The most advantageous amount is dependent upon anumber of variables. For example, the amount of resin which can mostadvantageously be applied depends somewhat upon the degree of crosslinking of the cellulosic fibers effected during the wet cross linkingoperation, and the particular type of resin being employed. It is ageneral rule that the greater the degree of wet cross linkage, thesmaller the amount of textile resin which need be employed, and one canobtain good results by employing only a relatively small amount of resinon a highly wet cross linked cellulosic fabric which are comparable tothose obtained by employing a larger amount .of textile resin on acellulosic material whose fibers have been wet cross linked to only aslight degree. In most instances, it is desirable to employ only a smallamount of the resin material and between about 2% to about 7% resinsolids, calculated on the weight of the dry material, generally givesthe desired results. Due to the synergistic action of the wet crosslinking agents and the textile resins employed in the process of thisinvention,

based on the weight of the material.

, loss of excess reagent.

the effectiveness of the textile resin is greatly increased as comparedto the prior art procedures of resin applications to cellulosic fabricsand satisfactory minimum care characteristics, e.g., flat dryingproperties and wrinkle resistance, can sometimes be obtained by theprocedure of this invention employing as little as 0.5% resin solids,

At the other extreme, as much as 10% to 15% resin solids, by weight ofthe material, can be employed, but the use of such large amounts ofresin is generally not necessary and is not economically desirable.

In a standard resin treatment, following the resin application, thematerial is dried and then cured at any suitable curing temperature.Usually the material is dried at a temperature lower than the curingtemperature, e.g., from about room temperature to 140 C. The mostadvantageous curing temperature depends upon the particular resin andcatalyst employed, but as a general rule a curing temperature in therange of from about C. to 200 C. with a temperature between about C. andabout 180 C. being more commonly employed. The curing temperature can bemaintained for from 10 sec onds to about 30 minutes or more with thepreferred range being from 30 seconds to 5 minutes, depending on thetemperature, amount and type of catalyst, and the particular textileresin employed.

The wet cross linking step of the general type employed with the processof this invention has also been employed in the textile trade, and thenecessary techniques will be apparent those skilled in the art. Forexample, the impregnating of the textile material with the selectedreagents can be accomplished in a manner similar to those employed inresin treatment. The material can be moistened by dipping in water,preferably containing the necessary catalyst, squeezed through rollersto achieve the desired take-up, and then contacted with the wet crosslinking reagent. If the alkaline or acidic catalyst is ap plied first,the usual procedure involves thereafter padding on the wet cross linkingagent or passing the material through a bath of the reagent per se or aconcentrated solution thereof in water or organic solvent. Excessivetension in this wet cross linking step is not ordinarily desired becauseof the tendency of tension to squeeze the retained during the crosslinking reaction.

The amount of the wet cross linking agent which should be reacted withthe cellulosic fabric can vary within relatively wide limits. Betweenabout 3% and about 30% calculated on the weight of the dry material, ofwet cross linking agent is ordinarily employed and more desirablyespecially when epichlorohydrin is used as the wet cross linking agent,between about 8% and about 12%. The wet cross linking agent or mixtureof wet cross linking agents is preferably applied in relatively pureform, i.e.,

without the use of a solvent or diluent, but due to the small degree ofcross linkage necessary in accordance with this invention, the wet crosslinking agent can be employed in an organic solvent or in most instanceseven in theform of an aqueous solution.

The wet cross linking agent can be applied by any suitable procedure andwhere a solution of the cross link ing reagent is employed, the solutionis preferably applied by padding followed by passing the materialthrough squeeze rolls to remove excess solution. It is generallypreferable to apply the cross linking reagent per se to the material bya distributing technique so that a limited quantity of the reagent canbe applied, thus avoiding Distribution of thepure reagent ll 7 7 uponthe material can be achieved by the use of sprays, Scotch rolls or otherapparatus of this type which per mits one to evenly distribute arelatively small quantity of a reagent upon a textile material.

The catalyst for the wet cross linking reaction is ordinarily employedin the form of an aqueous solution. The catalyst solution can be appliedto the material either before or after the wet cross linking agent isapplied. If precautions are'taken to prevent excessive side reactions,e.g., reaction of the wet cross linking agent with itself or with water,the catalyst and the cross linking agent can also be applied to thematerial simultaneously. Generally, it is preferred that an aqueoussolution of the catalyst be applied to the dry material prior to theapplication of the cross linking agent, e.g., by means of conventionalpadding equipment which permits the material to be immersed in anaqueous solution of the catalyst and thereafter squeezed or extracted toremove excess solution. Alternatively, the catalyst solution can beapplied by means of sprays, Scotch rolls, or in instances where the wetcross linking agent is applied first, the material can simply beimmersed in an excess of the basic solution of a proper concentrationand the reaction allowed to take place during the time the material isso immersed.

The amount of alkaline catalyst to be employed should be between about0.1% to about calculated on the weight of the dry material, i.e., it canbe varied over a Wide range. An amount less than about 13% andordinarily less than 10% is employed. As the alkaline catalyst isordinarily applied as an aqueous solution to the dry material, theseamounts are conveniently expressed in terms of the concentration of theaqueous catalyst solution. Thus an aqueous catalyst solution of thecatalyst of between about 0.5% and about 16% concentration willordinarily provide the desired amount of catalyst, the exactconcentration being governed in part by the catalyst, the amount of thesolution applied to the material, and the selected wet cross linkingagent.

If the wet cross linking agent consumes two chemical equivalents ofalkaline catalyst, as in the case of 1,3-dichloropropanol-Z, then about1.5 to 2.5 chemical equivalents of catalyst, calculated in the amount ofcross linking agent applied to the material, can suitably be employed.If a cross linking agent is employed which consumes only a chemicalequivalent of alkaline catalyst, as in the case of epichlorohydrin, thenabout 0.5 to 1.5 chemical equivalents of catalyst, calculated in theamount of cross linking agent applied to the material can be employed.With Wet cross linking agents which do not consume the catalyst, e.g.,the diepoxides and divinyl sulfone, correspondingly lesser amounts canbe employed. The pH of the treated material can be controlled byadjusting the ratio of wet cross linking agent to alkaline catalyst. Anonalkaline product can be achieved by employing a wet cross linkingagent which consumes the catalyst and less than a chemical equivalent ofthe catalyst. For example, excellent results are obtained using 8% to12% epichlorohydrin as the wet cross linking agent, calculated on theweight of the dry material, and between about 2.5% and 3.5% of sodiumhydroxide, calculated on the weight of the dry material, as a 3.5 to4.5% aqueous solution with an 80% to 90% uptake thereof. Astoichiometrically equivalent amount of another alkali metal hydroxidegives comparable result-s.

The amount of water in and on the material during the cross linkingreaction while not always critical, can

. alfect the result obtained, depending on the cross linking agentemployed. For example, if a high degree of cross linkage is desired, thetotal amount of water present in and on the material during the crosslinking reaction is of greater importance and should be limited so thatthe total amount of water present in the material is equal to not morethan 130% and preferably not more than about 100%, of the weight of thedry material, especially when the dihalohydrins and their equivalentsare employed. Ordinarily, more desirable results are obtained when notmore than about e.g., between about 60% and about 90%, of the weight ofthe dry material of water is present. These preferred conditions areconveniently achieved by dipping the material in Water containing theselected catalyst, squeezing the material to achieve the desired degreeof moisture uptake and then padding or spraying on the wet cross linkingagent per se in the desired amount. If the wet cross linking agent orcatalyst is volatile, it is preferred to maintain the treated materialin a closed container until the cross linking reaction has gone tocompletion to prevent excess loss of the reagent.

As previously mentioned, the wet cross linking reaction is conductedwhile the cellulosic fibers are in a wet, swollen condition and morespecifically the reaction should be conducted with the fiberssufiiciently wet so as to have an average diameter at least about 25%greater than the average diameter of the dry fibers. Usually as littleas 15%, calculated on the weight of the dry material, of water isrequired to achieve a wet, swollen condition for the cellulosic fibers,although at least 30% is preferred. It is not normally necessary,however, to measure the degree of swelling of the fibers for the reasonthat only minimal amounts of water is necessary to achieve measurableand adequate swelling. Quite obviously, because the fibers must be in awet, swollen condition, the reaction should be conducted at atemperature and under conditions which will not prematurely dry out thefibers. Normally, the reaction should be conducted at a temperatureconsiderably below C., although temperatures as high as 90 C. givesatisfactory results. The preferred temperature for. conducting the wetcross linking reaction is usually from about room temperature to about60 C. More reactive wet cross linking agents do not ordinarily requireexternal heat for the reaction to process at a satisfactory rate,especially when at least 3% alkaline catalyst is employed.

The time required for completion of the Wet cross linking reactiondepends upon the temperature, the type and amount of catalyst employed,and the particular wet cross linking agent used. Under conditionsfavoring a fast reaction and with highly reactive cross linking agents,sufiicient cross linkage can be obtained in only a minute or less, butin most instances at least about 5 minutes to 7 hours should be allowedfor the cross linking reaction to occur to a satisfactory extent. Ifonly sufficient cross linking agent or catalyst is applied to thematerial to give the desired degree of cross linkage, there is no needto control reaction time other than to insure that adequate time isallowed, e.g., a period of 24 or even 48 hours can be provided. However,if the cross linking reaction is conducted with the material in contactwith an excess of cross linking agent and catalyst, precautions shouldbe exercised to avoid excessive cross linkage of the material. For thisreason a procedure which involves applying limited quantities of the wetcross linking reagent or catalyst to the material is preferred.

As in the resin treatment, the wet cross linking is conducted in anessentially wrinkle free configuration.

Usually this is an essentially fiat condition unless a novelty finish isdesired. Thus, the wrinkle free configuration is ordinarily the same inboth the resin and wet cross linkage steps. The term flat when usedherein means smooth and fabric rolled up in a smooth roll is within theterm flat as used herein.

As stated hereinbefore, outstandingly superior results are obtained whenthe resin treatment is conducted before the wet cross linking step. Itis known that a resin treated fabric will lose some of its dry creaserecovery upon treatment with alkali and the results of extensiveexperiments have been published correlating this loss with a comitantgain in tensile strength. It has also been found that such treatmentincreases chlorine retention solution such that the pick up is about80%.

of resins tending to be sensitive to chlorine bleaches, an undesirableresult. However, when a resin treated material is wet cross linked withan alkaline catalyzed Wet cross linking agent, not only is the drycrease recovery of the resulting material not impaired, it is oftensubstantially improved, even when the alkaline catalyst is appliedbefore the cross linking agent. Equally surprising, the chlorineretentivity of the material is decreased instead of increased.Furthermore, the staining tendency of the fabric, e.g., when washed withother material which tend to lose their dyes, is less than materialwhich is wet cross linked first.

These and other surprising features of a resin first, wet cross linkedmaterial renders the process comprising a resin treatment followed by analkaline catalyzed wet cross link treatment distinctive from andpreferred over the reverse treatment.

In the example given hereinbelow, the treated fabrics were testedaccording to accepted standard methods. Tear strength was determined byTest A.S.T.M.D. Designation D142459. Dry Crease Recovery Angle wasdetermined by Test A.S.T.M.D. Designation D1295-53T. See A.S.T.M.Standards for Committee D-13 on Textiles (1959). lat dry ratings were byTest A.A.T.C.C. Designation T-88-1958.

The following examples are illustrative of the processes and products ofthis invention, but are not to be construed as limiting.

EXAMPLE I A sample of type 180 sheeting is padded with a 5% aqueoussolution of dimethylol methyl triazone resin containing 1% zinc nitrate,dried and then cured for minutes at 150 C. The fabric is then immersedin a freshly prepared aqueous solution containing 10% divinyl sulfoneand 1% sodium hydroxide, and the cloth is thereafter squeezed betweenrubber rolls to remove excess The wet fabric is rolled up into a neatroll, wrapped in polyethylene plastic and aged for 30 minutes. It isthen neutralized with dilute acetic acid and thoroughly washed anddried. The thus treated fabric has excellent minimum carecharacteristics.

Similarly, the above fabric can be reacted with any of the other textileresins described herein and then passed into the alkaline divinylsulfone solution. Alternatively, in the above-described reaction, thedesired amount of alkali-metal hydroxide solution, e.g., of aconcentration of from about 0.5 to about 5% and in an amount of fromabout 30 to about 130% of the weight of the dry fabric, can be appliedto the fabric and the fabric then passed into an aqueous solution ofdivinyl sulfone, e.g., of a concentration of from about 2 to about 20%.

EXAMPLE H A desized and bleached piece of 80 square cotton fabric istreated with an 8% aqueous solution of cyclic ethylene urea formaldehyderesin containing 1% zinc nitrate catalyst, dried and then cured for twominutes at 170 C. The fabric is then immersed in an aqueous solutioncontaining 6% divinyl sulfone and 2% sodium hydroxide, squeezed outbetween rubber rolls to a pickup of 60%, batched into a roll, wrappedwith polyethylene plastic and allowed to stand 30 minutes. The fabric isthen washed thoroughly and dried. The thus treated fabric has excellentdry crease recovery.

EXAMPLE 111 Example II is repeated except that the fabric is treatedwith a 10% aqueous solution of dimethyl ether of dimethylol ethyltriazone resin containing 2% monoethanol amine hydrochloride instead ofcyclic ethylene urea resin of Example 11. The results are substantiallythe same as in Example II.

' 1 .4 EXAMPLE IV A fabric is treated with dimethylol methyl triazoneresin in the manner described in Example III and the cured fabric isimmersed in an aqueous solution containing 14% 1,3-dichloropropanol-2maintained at C. The fabric is then squeezed between rubber rolls to apickup of 60% and is subsequently immersed into an aqueous solutioncontaining 10% sodium hydroxide and 15% sodium sulfate. This alkalinesolution is maintained at C. and the resin treated fabric is maintainedunder the surface of the alkaline liquid for a period of 30 seconds. Itis then squeezed out by the rubber rolls to remove excess liquid and iswashed until free of alkali. The thus treated fabric has excellentwrinkle resistance.

EXAMPLE V An 80 square cotton fabric is immersed in an aqueous solutioncontaining 7% Aerotex 23 modified melamine type textile resin (50%solids), 1% Surfonic N- polyethylene glycol nonylphenol wetting agent,0.85% zinc nitrate catalyst, and 6% Moropol 700 emulsified polyethylenesoftening agent and then squeezed through rubber rollers at 60 lbs.pressure to provide about an 85 solution uptake, calculated on the dryfabric. The fabric is then dried and cured while smooth in an oven atC., for one minute.

A portion of the above thus-treated fabric is then immersed in a 5%aqueous solution of sodium hydroxide and squeezed to provide about an80% uptake based on the dry fabric. The wet cloth is then contacted withepichlorohydrin so as to provide about a 10% uptake of epichlorohydrin,rolled up in a smooth roll and maintained at 55 C. overnight in a sealedpolyethylene bag.

The two portions of the fabric are then tested along with an untreatedcontrol for fiat drying properties. The results of such tests are shownbelow.

Increasing the resin solids to 4% and heating for one minute at 140 C.does not significantly alter the results. Note that both spin plus linedry and spin plus tumble dry flat dry ratings are improved to acommercially acceptable level.

EXAMPLE VI Portions of an 80 square cotton fabric which has been resintreated with about 9% (50% resin solids) Zeset MCdimethylcyclicethyleneurea textile resin catalyzed with zinc nitrate istreated with aqueous solutions of potassium hydroxide of varyingconcentration to provide about an 80% pickup, rolled up smooth in aplastic bag and maintained at 55 C. overnight and then Washed thoroughlyand dried.

Other portions of the same cotton fabric is subject to the sametreatment, but about 10-12% epichlorohydrin, cal- Increasing theconcentration of the alkali alone from 4 to causes increasing impairmentof dry crease recovery whereas increasing the concentration of thealkali from 4 to 10% with -1012% epichlorohydrin takeup cause increasingimprovement of dry crease recovery.

EXAMPLE VII An 80 square, 4 yard/ pound cotton fabric, resin treated inthe manner described in Example V1, is treated with 7% aqueous potassiumhydroxide, squeezed through rollers to provide about an 80% upstake, andthen padded with epichlorohydrin so as to provide various percentages ofO uptake, calculated on the dry fabric. The fabric is rolled up smooth,sealed in a polyethylene bag, heated at 55 C. overnight, and washedthoroughly and dried.

A cotton fabric which is identical to the above fabric, but not resintreated, is similarly treated.

The resulting samples are tested for flat drying properties andCI'GZlSfi recovery.

Table III Flat Dry Dry Crease Percent Properties Recovery Epichlo- Angle(Aver- Sample rohydrin age Warp Takeup Spin With Spin With and Fill),

Line Tumble degrees Drying Drying 40 1. No resin 4.8 2.6 1.0 68 2. Noresin. 7. 0 3.2 1. 0 71 3. No resin 10.0 2. 8 1.0 62 4. No res1n 15. 52. 2 1. O 70 5. No resin 16 2. 6 1. 0 69 6. No resin-.. 21 2.3 1.0 62 7.Resin treate 2.5 3.1 3.2 115 8. Resin treated- 5.5 4.6 3.0 117 9. Resintreated--. 8.5 4.5 3.0 117 10. Resin treated. 11. 5 4. 9 3.1 127 11.Resin treated. 14 4. 6 3.1 117 12. Resin treated 19 4. 3 3. 3 119 13.Resin only 1.0 2.5 98

The fabric which is not resin treated but is wet cross linked does nothave acceptable flat dry properties or dry crease recovery. The fabricwhich is resin treated and then Wet cross linked has markedly superiorfiat dry properties and dry crease recovery.

The relatively low spin dry ratings of the wet cross linked only samples(1-6) is due to rope lines present in the original fabric, i.e.,warpwise wrinkles present in the original fabric and resulting frombleaching, scouring and drying operations While the fabric is twisted ina rope-like state. Resin treatment alone or wet cross linking alone doesnot successfully remove these rope lines.

What is claimed is:

1. A process for improving the minimum care charac- 5 teristics of acellulosic textile material containing at least 1.8 free hydroxy groupsper anhydroglucose unit by cross linking the free hydroxy groups thereofconsisting essentially of the combination of steps of first applying tothe cellulosic material a textilecrease-proofing resin chemical crosslinking agent and chemically cross linking with the cross linking agentasuflicient portion of the free hydroxy groups of the cellulosicmaterial while the material is in an essentially dry, unswollencondition and in an essentially wrinkle free configuration to impartdrip dry fiat drying properties to the material by increasing its drycrease recovery and thereafter again applying to the cellulosic materiala wet textile crease-proofing chemical cross linking agent andchemically cross linking with the cross linking agent a sufficientportion of the free hydroxy groups of the cellulosic material While thematerial is in an essentially water Wet,.swollen condition and in anessentially wrinkle free configuration to impart spin dry flat dryingproperties to the material by increasing its wet crease recovery.

2. A process according to claim 1 wherein the cellulosic material iscotton.

3. A process according to claim 1 wherein the cellulosic material is inthe form of fabric.

4. A process according to claim 1 wherein the chemical cross linkingagent employed while the cellulosic material is in a dry, unswollencondition is an acid catalyzed textile resin.

5. A process according to claim 4 wherein the textile resin is anaminoplast.

6. A process according to claim 1 wherein the chemical cross linkingagent employed while the cellulosic material is in a wet, swollencondition is alkaline catalyzed.

7. A process according to claim 6 wherein the alkaline catalyzed crosslinking agent is epichlorohydrin and the amount of water present duringthe wet cross linking step is not more than about calculated on theweight of the dry cellulosic material.

8. A process for improving the minimum care characteristics of acellulosic textile fabric material containing at least 1.8 free hydroxygroups per anhydroglucose unit by chemically cross linking the freehydroxy groups of the cellulosic fabric consisting essentially of thesteps of first applying to the fabric an acid catalyzed textilecreaseproofing resin chemical cross linking agent and a catalyst for theresin and chemically cross linking with the textile resin a suificientportion of thefree hydroxy groups of the cellulosic material while thematerial is in an essentially dry, unswollen condition and the fabric isin an essentially wrinkle free configuration to impart drip dry flatdrying properties to the fabric by increasing its dry crease recoveryand thereafter applying to the fabric an alkaline catalyzed wet textilecrease-proofing chemical cross linking agent and an alkaline catalystfor the cross linking agent and chemically cross linking with the crosslinking agent a sufficient portion of the free hydroxy groups of theccllulosic material while the material is in an essential ly water wet,swollen condition and the fabric is in an essentially Wrinkle freeconfiguration to impart spin dry fiat drying properties to the fabric byincreasing its Wet crease recovery.

9. A process according to claim 8 wherein the fabric consistsessentially of cotton.

10. A process according to claim 8 wherein the textile resin is selectedfrom the group consisting of cyclic ethylene urea formaldehyde resins,melamine formaldehyde resins and triazone formaldehyde resins.

11. A process according to claim 8 wherein the alkaline catalyzed crosslinking agent is epichlorohyrin and the amount of water present duringthe wet cross linking step is not more than about 100% calculated on theweight of the dry fabric.

12. A process according to claim 8 wherein the alkaline catalyzed crosslinking agent is dichloropropanol and the amount of water present duringthe wet cross linking step is not more than about 100%, calculated onthe weight of the dry fabric.

13. A process according to claim 8 wherein the alkaline catalyzed crosslinking agent is a polyepoxide textile crease-proofing cross-linkingagent and the amount of water present during the wet cross linking stepis not more than about 100%, calculated on the weight of the dry fabric.

14. A process according to claim 8 wherein the alkaline catalyzed crosslinking agent is a sulfone activated divinyl compound.

15. A process for improving the minimum care characteristics of acellulosic textile fabric material containing at least 1.8 free hydroxygroups per anhydroglucose unit and consisting essentially of cotton bycross linking the free hydroxy groups thereof consisting essentially ofthe combination of steps of first applying to the fabric anacid-catalyzed textile crease-proofing resin selected from the groupconsisting of cyclic ethylene urea formaldehyde resins, melamineformaldehyde resins, and triazone formaldehyde resins and a catalyst forthe resin and chemically cross linking with the textile resin asufficient portion of the free hydroxy groups of the cotton while thecotton fibers are in a dry, unswollen condition and the fabric is in anessentially wrinkle free condition to impart drip dry flat dryingproperties to the fabric by increasing its dry crease recovery, andthereafter applying to the fabric epichlorohydrin and an alkali-metalhydroxide and chemically cross linking with the epichlorohydrin. in thepresence of not more than 100% water, calculated on the dry weight ofthe fabric, a sufficient portion of the free hydroxy groups of thecotton, while the cotton fibers are in a water wet, swollen conditionand the fabric is in an essentially wrinkle free condition to impartspin dry fiat drying properties to the fabric by increasing its wetcrease recovery.

16. A process for improving the minimum care characteristics of acellulosic textile fabric material containing at least 1.8 free hydroxygroups per anhydroglucose unit and consisting essentially of cotton bycross linking the free hydroxy groups thereof consisting essentially ofthe combination of steps of first applying to the fabric anacidcatalyzed textile crease-proofing resin selected from the groupconsisting of cyclic ethylene urea formaldehyde resins, melamineformaldehyde resins, and triazone formaldehyde resins and a catalyst forthe resin and chemically cross linking with the textile resin asufficient portion of the free hydroxy groups of the cotton while thecotton fibers are in a dry, unswollen condition and the fabric is in anessentially wrinkle free condition to impart drip dry flat dryingproperties to the fabric by increasing its dry crease recovery, andthereafter applying to the fabric dichloropropanol and an alkali-metalhydroxide and chemically cross linking with the dichloropropanol, in thepresence of not more than 100% water, calculated on the dry weight ofthe fabric, a sufficient portion of the free hydroxy groups of thecotton, while the cotton fibers are in a water wet, swollen conditionand the fabric is in an essentially wrinkle free condition to impartspin dry flat drying properties to the fabric by increasing its wetcrease recovery.

17. A process for improving the minimum care characteristics of acellulosic textile fabric material containing at least 1.8 free hydroxygroups per anhydroglucose unit and consisting essentially of cotton bycross linking the free hydroxy groups thereof consisting essentially ofthe combination of steps of first applying to the fabric anacid-catalyzed textile crease-proofing resin selected from the groupconsisting of cyclic ethylene urea formaldehyde resins, melamineformaldehyde resins, and triazone formaldehyde resins and a catalyst forthe resin and chemically cross linking with the textile resin asufiicient portion of the free hydroxy groups of the cotton while thecotton fibers are in a dry, unswollen condition and the fabric is in anessentially wrinkle free condition to impart drip dry flat dryingproperties to the fabric by increasing its dry crease recovery, andthereafter applying to the fabric a polyepoxide textile crease-proofingcross-linking agent and an alkali-metal hydroxide and chemically crosslinking with the polyepoxide, in the presence of not more than 100%water, calculated on the dry weight of the fabric, a sufficient portionof the free hydroxy groups of the cotton, while the cotton fibers are ina water wet, swollen condition and the fabric is in an essentiallywrinkle free condition to impart spin dry flat drying properties to thefabric by increasing its wet crease recovery.

18. A process for improving the minimum care characteristics of acellulosic textile fabric material containing at least 1.8 free hydroxygroups per anhydroglucose unit and consisting essentially of cotton bycross linking the free hydroxy groups thereof consisting essentially ofthe combination of steps offirst applying to the fabric anacid-catalyzed textile crease-proofing resin selected from the groupconsisting of cyclic ethylene urea formaldehyde resins, melamineformaldehyde resins, and triazone formaldehyde resins and a catalyst forthe resin and chem-ically cross linking with the textile resin asufficient portion of the free hydroxy groups of the cotton while thecotton fibers are in a dry, unswollen condition and the fabric is in anessentially wrinkle free condition to impart drip dry flat dryingproperties to the fabric by increasing its dry crease recovery, andthereafter applying to the fabic divinyl sulfone and an alkali-metalhydroxide and chemically cross linking with the divinyl sulfone, in thepresence of not more than 100% water, calculated on the dry weight ofthe fabric, a sufficient portion of the free hydroxy groups of thecotton, while the cotton fibers are in a Water wet, swollen conditionand the fabric is in an essentially wrinkle free condition to impartspin dry flat drying properties to the fabric by increasing its wetcrease recovery.

19. A process for improving the minimum care characteristics of acellulosic textile fabric containing at least 1.8 free hydroxy groupsper anhydroglucose unit and consisting essentially of cotton by crosslinking the free hydroxy groups thereof, consisting essentially of thecombination of steps of first applying to the fabric an aqueous solutionof between 2% and 7%, based on solids, of an acid-catalyzed textilecrease-proofing resin selected from the group consisting of cyclicethylene urea formaldehyde resins, melamine formaldehyde resins andtriazone formaldehyde resins, and an acid acting catalyst for the resin;drying the fabric and chemically cross linking a portion of the freehydroxy groups of the cotton with the textile resin While the fabric isdry and in an essentially wrinkle free condition by heating the fabricto a curing temperature between 100 C. and 200 C., thereby improving thedry crease recovery of the fabric; and thereafter applying to the fabricless than 10% of an alkali-metal hydroxide as an aqueous solution,followed by an alkaline catalyzed wet cross linking agent, andchemically cross linking a portion of the free hydroxy groups of thecotton fibers of the wet fabric with the cross linking agent, at atemperature between room temperature and. C., in the presence of beweenabout 15% and 90% water, thereby improving the wet crease recovery andfurther improving the dry crease recovery of the fabric, the percentagesof textile resin, alkali-metal hydroxide and water being calculated onthe dry weight of the fabric.

20. A process according to claim 19 wherein the alkaline catalyzed wetcross linking agent is epichlorohydrin.

21. A process according to claim 19 wherein the wet cross linking agentis dichloropropanol.

22. A process according to claim 19 wherein the Wet cross linking agentis a polyepoxide textile crease-proofing cross-linking agent.

23. A process according to claim 19 wherein the Wet cross linking agentis divinyl sulfone.

24. A process for improving the minimum care characteristics of acellulosic textile fabric containing at least 1.8 free hydroxy groupsper anhydroglucose unit and consisting essentially of cotton by crosslinking the free hydroxy groups thereof, consisting essentially of thecombination of steps of first applying to the fabric an aqueous solutionof betwen 2% and 7%, based on solids, of a melamine formaldehyde textileresin, and an acid acting catalyst for the resin; drying the fabric andchemically cross linking a portion of the free hydroxy groups of thecotton with the textile resin while the fabric is dry and in anessentially wrinkle free condition by heating the fabric to a curingtemperature between C. and 200 C., thereby improving the dry creaserecovery of the fabric; and thereafter applying to the fabric an amountof an alkali-metal hydroxide stoichiometrically equal to between about2.5% and 3.5% of sodium hydroxide as an aqueous solution, followed byepichlorohydrin and chemically cross linking a portion of the freehydroxy groups of the cotton fibers of the wet fabric with theepichlorohydrin, at a temperature between room temperature and '90 C.,in the presence of between about 15% and 90% water, thereby improvingthe wet crease recovery and further improving the dry crease recovery ofthe fabric, the percentages of textile resin, alkali-metal hydroxide andwater being calculated on the dry weight of the fabric.

25. Fabric produced according to the process of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,288,695 Fuller July 7, 1942 20 Pfeffer Dec. 17, 1946 Schoene Oct. 3,1950 Beer July 1, 1952 James June 1, 1954 Suen Jan. 10, 1956 SchroederDec. 18, 1956 Schroeder June 4, 1957 Marsh June 17, 1958 DAdamo June 2,1959 Gagarine May 23, 1961 FOREIGN PATENTS Great Britain Aug. 2, 1939Great Britain Apr. 13, 1955 OTHER REFERENCES Reeves, et a1.: TextileResearch Journal, vol. 25, 1955,

page 44.

1. A PROCESS FOR IMPROVING THE MINIMUM CARE CHARACTERISTICS OF ACELLULOSIC TEXTILE MATERIAL CONTAINING AT LEAST 1.8 FREE HYDROXY GROUPSPER ANHYDROGLUCOSE UNIT BY CROSS LINKING THE FREE HYDROXY GROUPS THEREOFCONSISTING ESSENTIALLY OF THE COMBINATION OF STEPS OF FIRST APPLYING TOTHE CELLULOSIC MATERIAL A TEXTILE CREASE-PROOFING RESIN CHEMICAL CROSSLINKING AGENT AND CHEMICALLY CROSS LINKING WITH THE CROSS LINKING AGENTA SUFFICIENT PORTION OF THE FREE HYDROXY GROUPS OF THE CELLULOSICMATERIAL WHILE THE MATERIAL IS IN AN ESSENTIALLY DRY, UNSWOLLENCONDITION AND IN AN ESSENTIALLY WRINKLE FREE CONFIGURATION TO IMPARTDRIP DRY FLAT DRYING PROPERTIES TO THE MATERIAL BY INCREASING ITS DRYCREASE RECOVERY AND THEREAFTER AGAIN APPLYING TO THE CELLULOSIC MATERIALA WET TEXTILE CREASE-PROOFING CHEMICAL CROSS LINKING AGENT ANDCHEMICALLY CROSS LINKING WITH THE CROSS LINKING AGENT A SUFFICIENTPORTION OF THE FREE HYDROXY GROUPS OF THE CELLULOSIC MATERIAL WHILE THEMATERIAL IS IN AN ESSENTIALLY WATER WET, SWOLLEN CONDITION AND IN ANESSENTIALLY WRINKLE FREE CONFIGURATION TO IMPART SPIN DRY FLAT DRYINGPROPERTIES TO THE MATERIAL BY INCREASING ITS WET CREASE RECOVERY.